Field of the Invention
The present invention relates to an air conditioner for a vehicle and a controlling method thereof, and more particularly, to an air conditioner for a vehicle and a controlling method thereof which can variably control a position of a rear seat cold air control door depending on a position of a front seat temperature-adjusting door when the position of the rear seat cold air control door is controlled according to rear seat air-conditioning modes (rear seat temperature-adjusting mode) in an air-conditioning case in which the rear seat cold air control door is mounted on a rear seat air passageway.
Background Art
An air conditioner for a vehicle is a car part, which is installed in a vehicle for the purpose of cooling or heating the interior air of the vehicle in the summer season or the winter season or removing frost from a windshield in the rainy season or the winter season to thereby secure a driver's front and rear visual fields. Such an air conditioner typically includes a heating device and a cooling device together, so that it can heat, cool or ventilate the interior air of the vehicle through the steps of selectively introducing the indoor air or the outdoor air into the air conditioner, heating or cooling the introduced air, and blowing the heated or cooled air into the vehicle.
Such an air conditioner for a vehicle has been developed in various forms according to kinds of vehicles or specifications of the same kind of vehicles, and for instance, there are single zone (front seat space) air conditioners, dual zone (right and left spaces of the front seat) air conditioners, and triple zone (right and left spaces of the front seat and a rear seat space) air conditioners.
FIG. 1 is a sectional view of a conventional single zone air conditioner for a vehicle. In FIG. 1, the air conditioner 1 includes: an air-conditioning case 10 having an air inflow port 11 formed at one side thereof and a defrost vent 12a, a face vent 12b and floor vents 12c formed at the other side thereof in such a way as to be adjusted in degree of opening by mode doors 16a, 16b and 16c; an evaporator 2 and a heater core 3 that are mounted on air passageways in the air-conditioning case 10 in order and are spaced apart from each other at a predetermined interval; and an air blower (not shown) connected to the air inflow port 11 of the air-conditioning case 10 for sending indoor air or outdoor air.
Moreover, the air conditioner further includes a temperature-adjusting door 15 mounted between the evaporator 2 and the heater core 3 for controlling temperature by adjusting the degrees of opening of a cold air passageway P1 bypassing the heater core 3 and of a warm air passageway P2 passing through the heater core 3.
The air-conditioning case 10 includes: an upper case 10a which is composed when a left case and a right case are assembled; and a lower case 10b assembled to a portion of the lower part of the upper case 10a on which the evaporator 2 is seated.
As described above, in the air conditioner 1 for the vehicle, in case of the maximum cooling mode, the temperature-adjusting door 15 opens the cold air passageway P1 and closes the warm air passageway P2. Therefore, the air blown by the air blower exchanges heat with refrigerant flowing inside the evaporator 2 while passing through the evaporator 2 and is changed into cold air. After that, the changed air flows toward a mixing chamber (MC) through the cold air passageway P1, and then, is discharged to the front seat space inside the vehicle through the vents opened by the mode doors 16a, 16b and 16c according to the predetermined air discharge mode, namely, the vent mode, the bi-level mode, the floor mode, the mix mode, or the defrost mode, such that the front seat space is cooled.
Moreover, in the case of the maximum heating mode, the temperature-adjusting door 15 closes the cold air passageway P1 and opens the warm air passageway P2. Accordingly, the air blown by the air blower passes through the evaporator 2, is changed into warm air by exchanging heat with cooling water flowing inside the heater core 3 while passing through the heater core 3 through the warm air passageway P2. After that, the changed air flows toward the mixing chamber (MC) and is discharged to the front seat space inside the vehicle through the vents opened by the mode doors 16a, 16c and 16c according to the predetermined air discharge mode, such that the front seat space is heated.
Furthermore, the dual zone air conditioner includes a separator (not shown) mounted in the middle of the inside of the air-conditioning case 10 to divide the inside of the air-conditioning case 10 into the right and left sides. In this instance, right and left temperature-adjusting doors which are operated individually are respectively mounted at both sides of the separator inside the air-conditioning case 10 to individually control temperature of the right and left spaces of the front seat.
Additionally, the triple zone air conditioner 1a includes a rear seat air passageway 20 formed below a front seat air passageway 17 having cold and warm air passageways P1 and P2 formed inside the dual zone air conditioner. Referring to FIG. 2, the triple zone air conditioner 1a will be described in brief. There is no difference between the dual zone air conditioner and the triple zone air conditioner in that an evaporator 2 and a heater core 3 are mounted inside an air-conditioning case 10, and a front seat temperature-adjusting door 15 and front seat mode doors 16a, 16b and 16c are mounted. However, the triple zone air conditioner 1a further includes: a rear seat air passageway 20 formed below the heater core 3; a rear seat temperature-adjusting door 25 mounted in front of the heater core 3 between the rear seat air passageway 20 and the warm air passageway P2; and an auxiliary rear seat temperature-adjusting door 26 mounted at the rear of the heater core 3.
In addition, the triple zone air conditioner 1a further includes a rear seat air outflow port 21 formed at an outlet of the rear seat air passageway 20 to discharge air to the rear seat.
Therefore, the triple zone air conditioner 1a controls a mixed ratio between cold air which passes the rear seat air passageway 20 by the rear seat temperature-adjusting door 25 and the auxiliary rear seat temperature-adjusting door 26 and warm air which meets the rear seat air passageway 20 after passing through the warm air passageway P2, and then, discharges the mixed air to the rear seat space through the rear seat air outflow port 21 so as to cool and heat even the rear seat space.
As shown in FIG. 2, the conventional triple zone air conditioner 1a mixes warm air passing through the warm air passageway P2 and cold air passing through the rear seat air passageway 20 and discharges the mixed air toward the rear seat to adjust temperature of the rear seat at the time of adjustment of the rear seat temperature that the rear seat temperature-adjusting door 25 opens all of the warm air passageway P2 passing through the heater core 3 and the rear seat air passageway 20. However, in this instance, the conventional triple zone air conditioner 1a has several disadvantages in that the triple zone air conditioner provides unsatisfactory rear seat temperature control, it is difficult to secure linearity of temperature discharged to the rear seat and it deteriorates passengers' comfort because a relatively large amount of cold air volume passes the rear seat air passageway 20 due to ventilation resistance of the heater core 3 at the side of the warm air passageway P2.
Moreover, the triple zone air conditioner 1a further includes a rear seat temperature-adjusting switch (not shown) mounted at the rear seat space so that the passenger can adjust temperature of the rear seat and control the rear seat temperature-adjusting door 25.
FIG. 3 is a graph showing discharge temperature depending on outdoor air temperature by positions (air-conditioning modes) of the rear seat temperature-adjusting switch. In FIG. 3, the rear seat temperature-adjusting switch can carry out total five air-conditioning modes, such as the maximum cooling mode, the cooling mode, the intermediate mode (temperature-adjusting mode), the heating mode and the maximum heating mode, according to manipulation positions, and discharge temperatures by the air-conditioning modes are shown in the graph of FIG. 3.
In FIG. 3, the three dotted line boxes show a discharge temperature range in the front seat heating mode, a discharge temperature range in the front seat intermediate mode, and a discharge temperature range in the front seat cooling mode.
As shown in FIG. 3, the conventional triple zone air conditioner 1a can make the rear seat in the maximum heating mode through the rear seat temperature-adjusting switch even though the front seat is in the cooling mode, and in this instance, a temperature difference between the front seat and the rear seat is very large.
As described above, the conventional air conditioner continuously supplies warm air or cold air to the rear seat unless someone manipulates the rear seat temperature-adjusting switch when a passenger on the rear seat gets out of the vehicle after manipulating the rear seat temperature-adjusting switch into the maximum heating mode or the maximum cooling mode because the rear seat temperature-adjusting door 25 is controlled just by the rear seat temperature-adjusting switch regardless of the position of the front seat temperature-adjusting door 15.
In this instance, if warm air is continuously supplied to the rear seat space while the front seat is cooled, the conventional air conditioner has several disadvantages in that warm air of the rear seat influences on the front seat to deteriorate comfort of the passenger who sits on the front seat and in that temperature of the inside of the vehicle rises due to the warm air supplied to the rear seat so as to increase an operation section of the air conditioner.